Flashcards in Gastric motility Deck (53):
What is gastroparesis?
Decreased gastric motility (NOT a total shut down)
What is the migrating motor complex?
GI motor activity that starts in the stomach, and sweeps over the upper GI tract about every 90 minutes
What happens to the migrating motor complex during the fed state?
No longer migrating--constant motor activity
What are the three general types of GI motor activity?
What causes the storing effect of the GI tract?
What are the two steps of gastric storing/filling?
What happens during the receptive relaxation phase of gastric storing? (2)
Relaxation of LES and stomach in anticipated by food
Rise in gastric volume, without change in pressure
What is the innervation of receptive relaxation reflex of the stomach?
What initiates the receptive relaxation of the stomach?
What is the signalling used in receptive relaxation to relax the LES?
Non Cholinergic and nonadrenergic (NO mediated)
What happens in gastric accommodation?
Stomach relaxation in response to gastric filling
Dilation of fundus
What primarily regulates gastric accommodation? What modulates it?
What happens to volume/pressure in gastric accommodation?
Increase in volume without increase in pressure (just like the bladder)
What are the three parts of gastric churning?
What is propulsion part of gastric churning?
Movement of stomach contents against the pyloric region
What happens to the pyloric sphincter during gastric churning?
What initiates the propulsion part of gastric churning?
Pacemaker cells near the greater curvature of the stomach
What is retropulsion part of gastric churning?
Pulverization and shearing of food particles by contractions
What is the overall goal of gastric churning?
Increased surface area of food
What happens in the grinding phase of gastric churning?
Food is trapped in the antrum
When do particles larger than 2 mm pass into the duodenum?
Interdigestive period (2 hours later)
The rate of gastric emptying is dependent on what?
The content of ingested material
What happens to rate of gastric emptying with increasing protein and fat?
Lowers rate of emptying
What controls the rate of gastric emptying?
Neuronal and hormonal control
What three hormones play a role in gastric emptying?
What are the four NTs utilized in gastric emptying?
HCl in the duodenum stimulates what hormone to be secreted? Result?
Secretin = impaired gastric emptying, increase HCO3 production from the pancreas
Fat in the duodenum primarily stimulates what hormone to be secreted? Result?
CCK --impaired gastric empyting
Protein in the stomach stimulates what hormone to be secreted? Result?
Gastrin-- impaired gastric emptying
Duodenal distension in the duodenum stimulates what? Result?
ENS--impaired gastric emptying
Vagal stimulation in the duodenum stimulates which three neurotransmitters that impair gastric emptying?
Ach, opioid, 5HT = impaired gastric emptying
What are the four targets of CCK?
Sphincter of Oddi
What is the effect of CCK on the gallbladder?
What is the effect of CCK on the pancreas?
What is the effect of CCK on the the stomach?
What is the effect of CCK on the sphincter of Oddi??
Gastroparesis is frequently associated with what?
Impairments of the pyloric region or pyloric sphincter itself (DM neuropathy/ infantile pyloric stenosis)
What are the events involved in emesis?
Afferent fibers activated, which trigger the vomiting center, causing a reverse wave of peristalsis
What is the stimulus for an emetic response?
Irritation of the GI mucosa
What are the nerve fibers activated in emesis?
What is the purpose of increased saliva prior to emesis?
The emetic response is coordinated by what nerve?
Vagal afferents and emetic center of the brain
What is the purpose of secondary peristalsis in emesis?
Returns esophageal material back to the stomach
What are the two stimuli for secondary peristalsis?
Stretch and lower pH
What are the four key neurotransmitters for sensory information from the gut to be relayed back to the CNS?
5-HT, Ach, histamine, and D2
What muscarinic receptors are located in the chemoreceptive trigger zone?
Motion sickness is mediated through what two receptors on the cerebellum?
Histamine and Ach
Why can uncontrolled DM lead to gastroparesis?
What is the key neurotransmitter in the intestines?
What happens in retching?
occurs when the upper esophageal sphincter does not relax and the contents of the stomach are not expelled
What are the three receptors in the chemoreceptor trigger zone (which stimulates the emetic center of the brain)?
5HT, D2, M1
What are the neurotransmitter receptors on the NTS (which stimulates the emetic center of the brain)?